Patent Document 1 discloses a steering locking device of the related art. As shown in FIGS. 1 and 2, a steering locking device 100 includes a locking member 102, a driving body 103, and an auxiliary locking member 104. The locking member 102 is urged by a coil spring 101 in a direction to an unillustrated steering shaft of an automobile (an upward direction in FIGS. 1 and 2), and is fittable to the steering shaft. The driving body 103 is configured to drive the locking member 102. The auxiliary locking member 104 is arranged near the locking member 102 and capable of locking the locking member 102 at a locked position. The driving body 103 includes a rotating member 106 and a cam member 107. The rotating member 106 is configured to be driven by a motor 105 via an unillustrated worm. The cam member 107 is configured to be reciprocated in moving directions of the locking member 102 by the rotation of the rotating member 106. The cam member 107 is coupled to the locking member 102 with a coupling pin 108.
The auxiliary locking member 104 has an engagement protrusion 110 engageable with an engagement groove 109 in a side portion of the locking member 102 and is urged in a direction to the locking member 102 by a spring member 111. A holding portion 113 is provided extending from a back surface of a housing cover 112 to the auxiliary locking member 104 in the moving direction of the locking member 102. A front end of the holding portion 113 is engaged with an engagement groove portion 114 of the auxiliary locking member 104, and thereby the auxiliary locking member 104 is kept separated away from the locking member 102.
In the aforementioned configuration, when the motor 105 is rotated in a locking direction while the automobile is parked, a driving force of the motor 105 rotates the rotating member 106 to move the cam member 107 in the locking direction (the upward direction in FIG. 1) of the locking member 102, and thus the urging force of the coil spring 101 displaces the locking member 102 to the locked position. As the result, a front end of the locking member 102 is fitted to the steering shaft, and rotation of the steering shaft is prevented. Thus, the automobile becomes unsteerable.
Thereafter, when the motor 105 is rotated in an unlocking direction, the rotating member 106 is rotated in a reverse direction, and the locking member 102 together with the cam member 107 is displaced to an unlocked position. As the result, the locking member 102 is released from the steering shaft, and the steering shaft is allowed to rotate freely. Thus, the automobile becomes steerable.
In the locked state shown in FIG. 1, the holding portion 113 protrudes from the back surface of the housing cover 112 toward the auxiliary locking member 104, and the front end of the holding portion 113 is engaged with the engagement groove portion 114 of the auxiliary locking member 104. Thereby, the auxiliary locking member 104 is kept separated away from the locking member 102. After that, as shown in FIG. 2, when the housing cover 112 is removed while the vehicle is parked, the holding portion 113 is disengaged from the engagement groove portion 114 of the auxiliary locking member 104, and thus the auxiliary locking member 104 is urged in the direction to the locking member 102 by the spring member 111, so that the engagement protrusion 110 is engaged with the engagement groove 109 in the side portion of the locking member 102. This causes the locking member 102 to be kept at the locked position, thus preventing the rotation of the steering shaft. It is possible to prevent a problem that the vehicle is made steerable by an unauthorized unlocking operation and thus to enhance vehicle theft prevention at the time of parking of the vehicle.